Some things you should keep in the safe deposit box at your bank are:
- originals of important documents, such as birth certificates, property deeds, car titles
- family keepsakes
- photos you can’t replace
Cash is not a good thing to keep in the safe deposit box because it is not protected by FDIC insurance.
Source: https://www.fdic.gov/consumers/consumer/news/cnwin18/fivethings.html